The use of solar energy to supplement and replace, in part, reliance on conventional energy sources such as oil, coal, and other fossil fuels, has become a matter of national concern and the subject of increasing technological research. As our source of fossil fuels is gradually depleted and we are forced to rely on increased imports of foreign oil, resulting in increasing trade deficits, the necessity for developing new sources of energy becomes apparent. While nuclear reactors may be a partial solution to our problem, at the present state of development, this source of energy has proved extremely costly and the disposal of waste products poses a problem.
Development of efficient solar heating devices and systems, particularly in those sections of the country blessed with an abundance of sunshine, seems to be a logical approach in an effort to alleviate our energy crisis. Solar energy offers many advantages in that the supply seems endless and it provides a clean source of heat without resulting in any objectional end products.
Various types of solar heating systems have been proposed, including for example, heating units which constitute a structural part of the roof of a building, as shown in the U.S. Patent to Moore, No. 4,010,733, and the U.S. Patent to Warren, No. 4,029,080. Units of this type, being an integral part of the building, are necessarily restricted to use in a single location and cannot be readily moved without material alteration or reconstruction of the building.
In smaller units, in order to make more effective use of sunlight, a system of lenses has been used to concentrate or focus the sunlight on a heat collecting surface, such as metal, submerged in a heat transfer fluid, which is circulated through the heating unit and through a heat exchanger. The solar heating unit may be mounted for tracking with the sun so as to maintain the lens system in focus with the sun's rays during daylight hours. Devices of this type are disclosed, for example, in the U.S. Patents to Manly, No. 2,902,028; Rogers, No. 3,929,121, and Minnich, No. 3,981,295.
The present invention relates to a solar heating system incorporating a heating unit or panel of the latter type in which an improved heating unit has been devised to effect a more efficient conversion of solar energy to heat in which a fluid heat transfer medium, such as water, to which an anti-freeze agent may be added, is circulated through the heating unit and a heat exchanger.
I have discovered that more effective use of the sun's rays is obtained by using an insulated cover for the tank of the heating unit, the cover having a series or plurality of apertures, preferably of conical shape, each located below one of the lenses, the sun's rays being focused by the lenses onto a heat absorbing metal surface located directly below each aperture and in contact with or submerged in the fluid heat transfer medium, as more fully described in the following specification and accompanying drawings.